function [ Ninv] = inverse_incremental( Minv, b, c )
%INVERSE_INCREMENTAL block matrix formula
%   Detailed explanation goes here
 p = b'*Minv;
 q = 1 /(c - p*b);%scaler
 temp = q*p;
 Ninv = [Minv+p'*temp,-temp';-temp,q];

end

